diff options
| -rw-r--r-- | src/algebra/ChangeLog | 5 | ||||
| -rw-r--r-- | src/algebra/syntax.spad | 36 |
2 files changed, 37 insertions, 4 deletions
diff --git a/src/algebra/ChangeLog b/src/algebra/ChangeLog index bea5710e..278e4ff3 100644 --- a/src/algebra/ChangeLog +++ b/src/algebra/ChangeLog @@ -1,3 +1,8 @@ +2007-12-06 Gabriel Dos Reis <gdr@cs.tamu.edu> + + * syntax.spad (Syntax): Add explicit conversion functions from + Syntax to Integer, DoubleFloat, Symbol, and String. + 2007-12-05 Gabriel Dos Reis <gdr@cs.tamu.edu> * syntax.spad (Syntax): Conversions to Integer, DoubleFloat, diff --git a/src/algebra/syntax.spad b/src/algebra/syntax.spad index 4962975c..80bee21e 100644 --- a/src/algebra/syntax.spad +++ b/src/algebra/syntax.spad @@ -54,16 +54,28 @@ Syntax(): Public == Private where ++ e.g. a sequence of cons cell ending with nil. coerce: Integer -> % - ++ convert(i) injects the integer value `i' into the syntax domain + ++ coerce(i) injects the integer value `i' into the Syntax domain + + convert: % -> Integer + ++ coerce(i) extracts the integer value `i' from the Syntax domain coerce: DoubleFloat -> % - ++ convert(f) injects the float value `f' into the syntax domain + ++ coerce(f) injects the float value `f' into the Syntax domain + + convert: % -> DoubleFloat + ++ convert(f) extracts the float value `f' from the Syntax domain coerce: Symbol -> % - ++ convert(s) injects the symbol `s' into the syntax domain. + ++ coerce(s) injects the symbol `s' into the Syntax domain. + + convert: % -> Symbol + ++ convert(s) extracts the symbol `s' from the Syntax domain. coerce: String -> % - ++ convert(s) injects the string value `s' into the syntax domain + ++ coerce(s) injects the string value `s' into the syntax domain + + convert: % -> String + ++ convert(s) extract the string value `s' from the syntax domain buildSyntax: (Symbol, List %) -> % ++ buildSyntax(op, [a1, ..., an]) builds a syntax object for op(a1,...,an). @@ -101,15 +113,31 @@ Syntax(): Public == Private where coerce(i: Integer): % == i pretend % + convert(i: %): Integer == + not integer? rep i => userError "invalid conversion target type" + i pretend Integer + coerce(f: DoubleFloat): % == f pretend % + convert(f: %): DoubleFloat == + not float? rep f => userError "invalid conversion target type" + f pretend DoubleFloat + coerce(s: Symbol): % == s pretend % + convert(s: %): Symbol == + not symbol? rep s => userError "invalid conversion target type" + s pretend Symbol + coerce(s: String): % == s pretend % + convert(s: %): String == + not string? rep s => userError "invalid conversion target type" + s pretend String + buildSyntax(s: Symbol, l: List %): % == -- ??? ideally we should have overloaded operator `per' that convert -- from list of syntax to syntax. But the compiler is at the |